1. Field of Invention
The invention relates to a vascular anchoring device intended to be introduced into a blood vessel by a catheter and including braces that are expandable in the radial direction.
2. Background Information
In order to position intravascular surgical tools or treatment aids, catheters are usually employed, which enable the expansion of blood vessels by arranging balloons of a balloon catheter or the insertion of stents or surgical tools for operative interventions into blood vessels. As a rule, the catheter is introduced via a blood vessel such as, for instance, the femoral artery or the brachial artery in order to render feasible the required treatment on the respective site. Such an intervention, however, always entails the risk of particles and, in particular, plaque particles being released from the vessel wall into the bloodstream, thus causing damage and, in particular, embolisms and hence an interruption or throttling of the blood supply to the target tissue. It has, therefore, been already suggested in this context to use filter systems that are capable of capturing the particles released during an intervention. Known filtering systems as are described, for instance, in U.S. Pat. No. 5,300,086 comprise braces which are expandable in the radial direction and between which a filter material can be tentered radially. In that known device, the braces are designed to be biased in the radial direction and maintained in the folded position by a cladding hose which is introduced together with the guide wire and the filter. By retracting the cladding hose, it is subsequently feasible to move the braces outwards under the biasing force. When fixing such braces in a blood vessel, the guide wire is, however, no longer freely movable and, in particular, no longer movable in the axial direction beyond the site on which the radially expandable braces are in contact with the vessel wall. The bracing force is limited by the elastic prestress of the braces. In order to retract or fold these radially expanded braces, a hose-like applicator can again be lapped over the braces to effect their inward movement against the biasing force or the spring force of the braces, respectively. While the braces are opened by a tensile movement, their closure is effected by a thrust movement of the actuation member in the opposite direction.
From FR-2 580 504 A, a device for positioning an intravascular filter is, moreover, known. In that device, a blood filter capable of being inserted by means of a catheter and a guide wire and reversibly expanded by means of an inflatable balloon is described, which can be anchored within a vein. The blood filter is comprised of several flexible arms.